Behavioral Variability Management in Beginning Communicators This application seeks support to continue a long-term program of study aimed at effective management of behavioral variability in response to procedures designed to establish behavioral prerequisites for symbolic communication in children with neurodevelopmental disabilities. Our primary study population will be children with autism spectrum disorders (ASDs) who exhibit little or no apparent comprehension of spoken language and whose primary mode of communication is nonverbal. A major goal of our program has been and will continue to be to assess the potential of such children to exhibit true symbolic relations, defined operationally in terms of equivalence between physically dissimilar stimuli (e.g., between symbol and referent). A second goal, emphasized in the present project, will be to uncover and manage sources of behavioral variability in acquisition of symbolic relations. To structure our program, we will extend an approach that has achieved a directly related goal with stimulus equivalence defined by shared physical features (i.e., stimulus relations based on physical identity/similarity). Our targets will include: (a) auditory perception, discrimination, and relational learning, (b) basic and emergent symbol-referent mapping, and (c) intra- and cross-modal equivalence class formation. To supplement and complement our studies of children with ASDs, we will expand an international partnership with researchers in Brasil who are pursuing directly related research. Via this partnership, we will be able to include at little added cost a population of children with pre-lingual deafness who are recent recipients of devices that establish hearing capabilities (e.g., cochlear implants). These children also exhibit variability in acquisition of symbolic relations, thus presenting a contrast population whose symbolic relational deficits are attributable to sensory deprivation rather than ASDs. Results of our studies are likely to have significance not only for theory but also for clinical intervention with children who show deficits in acquiring symbolic relations, particularly those children who are or who may become candidates for augmentative/alternative communication training.